Principal Investigator: Louise C. Ivers MD MPH DTM&H
A “seroprevalence study” tests a person’s blood sample for the presence of antibodies. It gives a better estimate of the number of people that have been infected with SARS-CoV-2, the virus that causes COVID-19. We conducted a seroprevalence study in Holyoke, Massachusetts, to estimate how many people were previously infected with SARS-CoV-2, identify high-risk groups, and guide public health responses to the pandemic.
We invited 2,000 randomly selected addresses between 11/5/2020 – 12/31/2020. Participants completed questionnaires and gave a blood sample for antibody testing. We enrolled 280 households including 472 individuals. 328 underwent antibody testing. The seroprevalence of SARS-CoV-2 IgG antibodies was 13.1% for the entire city. It was 16.1% among Hispanic individuals compared to 9.4% among non- Hispanic white individuals. Spanish speaking households (21.9%) had a higher seroprevalence compared
to English speaking households (10.2%), as did individuals living in high- (14.4%) compared to low- vulnerability areas (8.2%).
SARS-CoV-2 antibody seroprevalence in Holyoke was only 13.1% during the second surge in 2020, meaning a large part of the population remained at risk. Hispanic individuals were at high risk of prior infection. SARS-CoV-2 exposure disparities require proactive public health interventions to ensure at-risk communities have appropriate access to vaccines, testing, and treatment.
We conducted a SARS-CoV-2 seroprevalence study in Holyoke, Massachusetts, US to estimate the seroprevalence of antibodies, risk factors for seropositivity and inform public health responses to COVID- 19.
We invited 2,000 randomly sampled addresses between 11/5/2020 – 12/31/2020 to complete questionnaires and provide dried blood spots for SARS-CoV-2 antibody testing. We calculated IgG antibody seroprevalence estimates using a Bayesian procedure that incorporates uncertainty in test sensitivity and specificity.
We enrolled 280 households including 472 individuals. 328 underwent antibody testing. Citywide seroprevalence of SARS-CoV-2 IgG was 13.1% (95%CI 6.9-22.3). Seroprevalence was 16.1% (95%CI 6.2-31.8) among individuals identifying as Hispanic compared to 9.4% (95%CI 4.6-16.4) among those identifying as non-Hispanic white. Seroprevalence was higher among Spanish speaking households (21.9%; 95% CI 8.3-43.9) compared to English speaking households (10.2%; 95% CI 5.2-18.0) and among individuals living in high- (14.4%; 95% CI 7.1-25.5) compared to low-vulnerability areas (8.2%; 95% CI 3.1-16.9).
SARS-CoV-2 seroprevalence of IgG antibodies in Holyoke was only 13.1% during the second surge in 2020 highlighting the need for expanding vaccination. Individuals identifying as Hispanic were at high risk of prior infection. Disparities in SARS-CoV-2 exposure require proactive public health interventions to ensure at-risk communities have appropriate access to vaccines, testing, and timely treatment.
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